Lipase of Penicillium notatum was purified to electrophoretic homogeneity by ammonium sulphate precipitation, ion-exchange, and hydrophobic interaction chromatography. The purified enzyme displayed a solitary band in the 46-kDa region on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The pH and temperature optima were found to be 9.5 and 40 A degrees C, respectively. It showed stability over broad pH range (pH 6.0-12) and higher thermal tolerance with half-lives (t (1/2)) of 8.25, 3.2, 1.12, and 0.58 h at 40, 50, 60 and 70 A degrees C, respectively. The K (m) and V (max) values for p-nitro phenyl palmitate (pNPP) hydrolysis were 3.33 mM and 232.6 A mu mol/mL min(-1), respectively. The energy of activation for denaturation E-a(d) was 81.1 kJ/mol, whereas the entropy (Delta S-*), enthalpy (Delta H-*) and free energy (Delta G(*)) of thermal inactivation of lipase were recorded to be -0.083 Jmol(-l) K-l, 78.48 and 104.54 kJ/mol, respectively, at 40 A degrees C. The enzymatic activity was substantially improved by Ca2+ and Mg2+, and suppressed in the presence of Co2+ (,) Cd2+, Pb2+ and Fe3+ ions to various levels. Exposure to hydrophobic environment did not affect the enzyme stability; however, protease solution deactivated the enzyme. Considering all these properties, this fungal lipase would be an interesting candidate for future organic synthesis application. Graphical Abstract [GRAPHICS] .